She was dressed in a high-neck black blouse and slim black pants, funereal business casual. Her jewelry was what stood out: She wore plastic stud earrings the size and shape of marbles, a rubbery-looking hoop in the cartilage of her left ear, and an ovular silver pendant depicting a trio of conical spires around her neck. It was Lalish, she informed me, the Yazidi’s holiest place, a temple in northern Iraq. The necklace had been a present from an Iraqi girl she’d met in New York.

Slight, reserved, and grave, reticent to make eye contact and soft-spoken, Murad looked about as out of place among the boisterous, jostling lunch-rush crowd as she said she felt earlier this month, while speaking at the U.N. after accepting her Goodwill Ambassadorship for the Dignity of Survivors of Human Trafficking.

“I was a farmer, a villager, and I was born to be such,” Murad declared to a rapt and tearful audience, including U.N. Secretary- General Ban Ki-moon. “I had hopes, common to all young girls of my village. I was not raised to give speeches, neither was I born to meet world leaders, nor to represent a cause so heavy and so difficult.”

The Yazidis are a small sect of non-Muslims who live in Iraq, Syria and Turkey—they practice a religion that draws from several faiths—who have become a particular target of systematic ISIS violence. In August 2014, ISIS militants attacked Murad’s village of Kocho and executed her mother and six of her brothers. With her younger female relatives and friends, Murad, on summer break from school, was kidnapped and sold at a slave market to an ISIS fighter who kept her captive for weeks, brutally abusing and raping her until she finally escaped and ultimately sought refuge in Germany. In the two years since, she has emerged as a forceful spokesperson and advocate for her besieged people on the world stage.

Motherless, displaced, traumatized, grief-stricken, and the ongoing recipient of ISIS death threats, Murad counts herself among the lucky: Of the 6,000 Yazidi women and children taken during ISIS raids, she estimated that more than 3,200 are still being held in captivity. The activist highlighted one person in particular: Lemya, a neighbor and the little sister of close friends, who was only 14 when she was taken and held in the Iraqi city of Mosul by a 34-year-old man, who both raped her and told her, confusingly, that she remained a virgin. “That always sticks in my mind,” Murad explained. “That this happened to her, and she never knew what had happened to her.”

Lemya, like so many other Yazidis, remains missing. And it’s largely for their sake that Murad has sought the help of London-based human rights lawyer Amal Clooney. Together they’re attempting to remind the world that the organized killing and enslavement of Yazidis constitutes genocide. Their goal is to wrangle the assistance of the U.N. in hopes of holding ISIS accountable in international court.

“It is a genocide, and it needs to be recognized,” Murad told me through her interpreter, Murad Ismael, executive director of the Yazidi-supporting nonprofit Yazda. “That must be acknowledged, not just for Yazidis, but for any community that suffers through this. When genocide is committed, it must be seen. People must look at it with open eyes, not minimize its impact.”

Speaking at the U.N. just after her client, Clooney referred to ISIS’s “bureaucracy of evil on an industrial scale,” and cited, as evidence, several entries in an official Islamic State pamphlet titled “Questions and Answers on Taking Slaves.” (One stomach-turning example: “Is it permissible to have intercourse with a female slave who has not reached puberty? Yes, but if she is not fit for intercourse, then it is enough to enjoy her without intercourse.”)

By email, Clooney bemoaned that “so far there has not been a single member of ISIS who has faced trial for the genocide against the Yazidis,” and explained that she’s putting forth a proposal for the U.N. Security Council to send a team of investigators to Iraq to gather evidence that can later be used in international criminal court and by national prosecutors, and to identify ISIS suspects who can be served with financial sanctions. “This ‘ISIS commission,’” Clooney wrote, “would investigate crimes committed against all Iraqis, including Sunnis, Shias, and Christians, as well as Yazidis. And it should do so now before evidence is lost forever. Witnesses are dispersing and other evidence is disappearing. We already know of more than 50 mass graves in Iraq that lay unprotected and unexhumed.”

Sitting across from me at a small table, picking at her rapidly congealing food and sipping a lemon-lime Gatorade, Murad looked exhausted. She’d spent the past week traveling the U.S., meeting with ambassadors and foreign ministers. She’d attended parties thrown in her honor, like a swanky shindig at Tina Brown’s house to announce the launch of Murad’s newest endeavor, Nadia’s Initiative, which will develop programming to help the many refugees, Yazidi and not, whom she’s encountered in the past two years. She also spoke at the U.N. for a second time, at a high-level plenary meeting of the General Assembly about refugees and migrants “The world has only one border,” she beseeched the assembled dignitaries. “It is called humanity. The differences between us are small compared to our shared humanity. Put humans first.”

To me, she acknowledged: “It’s not easy to come and say the same message, speak to the same institution, to the same people, when things have not changed. But at the same time, because nothing’s changing, I have to come back and remind them, say: This is still happening.”

To be an activist is to live fiercely in the present as a means of safeguarding the future, to hollow out one's own life for the benefit of others. That selflessness was a quality Clooney identified when I asked why she was moved to take on Murad’s case. “She feels the pain of what happened to other women in her community as if it were her own,” the barrister wrote. “And she is unable to go on with her own life while there are still 3,200 women and children being held in ISIS captivity and while her community struggles to find a safe home.”

But with Murad there’s a level of self-abnegation that’s unnerving. She still receives ISIS death threats—at Brown’s party, Clooney spoke of one delivered to her client in the form of a voice mail from an enslaved young cousin—but the activist told me she’s numb to them. “I don’t think anything will stop me,” she contended, “because what they’ve done caused the maximum pain. I don’t think they can do anything worse.” When I asked her what she hopes her life will look like in a decade, or two, or three, she gave me her briefest, most dispassionate answer: “I don’t see my future. Not even tomorrow.”

It struck me not exactly as hopelessness, but as an unwillingness to go there. After all, there’s still too much work to be done. And in that work, Murad seems to find a sense of healing, a balm for wounds that remain palpably, understandably, raw. “I never thought in my life, I’d be sold,” she reminded the crowd at Brown’s house. “It’s painful to say, as a human, ‘I was sold.’”

How, then, I asked, did it feel to be anointed by the U.N., to be recognized as a person of significance? “The terrorists who have done these things to me, to us, they humiliated us,” she replied. “They gave us no value. So for me to stand beside Ban Ki-moon, for someone like him to acknowledge me, to respect me, that’s a message to Daesh. Good people are welcoming me, are embracing me. That’s what made me happy.